Latch mechanism for sequential controller



March 24, 1959 2,878,686

LATCH MECHANISM FOR SEQUENTIAL CONTROLLER A. H. GERHARDT ETA].

Filed Dec. 29, 1955 :mJU

United States PatentO LATCH MECHANISM FOR SEQUENTIAL CONTROLLER Andrew H. Gerhardt, Benin, and Robert D. Tr'iplett, Carterville, Ill., assignors to Borg-Warner Corporation, Chicago, 111., a corporation of Illinois Application December 29, 1955, Serial No. 556,357 3 Claims. (Cl. 74-4243) This invention relates to linearly arranged sequential controllers and more particularly to a latch or lock mechanism for such controllers.

A sequential controller with which the present invention may be associated is disclosed and described in Puerner et al. Patent 2,641,661, issued June 9, 1933.

In said patent, a carriage carrying a plurality of pairs of electrical contacts is disposed within a housing and is movable along a linear path within the housing. A linearly arranged lead screw is also disposed within the housing and is fitted with a clock works for rotating the lead screw in a predetermined direction. There is no axial movement of the screw. Means are provided for placing the carriage in threaded engagement with the lead screw so that upon rotation of the screw the carriage carrying the contacts is propelled in an axial direction along the lead screw.

The electrical contacts are provided with trolleys or wipers which may take the form of leaf springs. The wipers bear against a corresponding number of bus bars disposed linearly and in a generally parallel fashion in the rear wall of the housing. Suitable electrical connections are provided to each bus bar so that electrical current may be supplied to the contacts through the trolleys. The rear wall is formed of an insulating material and is provided with a plurality of linearly arranged cams or contoured strips disposed intermediate the bus bars. The cams are engaged by corresponding followers projecting from at least one contact of each pair of contacts. As the carriage is propelled in a linear path and in a predetermined direction by the screw, the pairs of electrical contacts are actuated to control electrical circuits as the followers traverse the linearly arranged cams.

Obviously, any desired number of contacts may be mounted upon the carriage and any desired cam contour may be provided upon the rear wall of the housing to bring about operation of the contacts in accordance with any desired permutation or combination.

In the controller of said patent, the carriage is proinvention to provide a latch mechanism for maintaining vided with a slide formed with a pair of ears or lugs.

The slide may be moved relative to the lead screw and the carriage until the ears straddle and engage a groove between adjacent threads of the lead screw. The result is that the slide and the lead screw are brought into threaded engagement, the ears serving as what might be termed a nut having an interrupted thread. Rotation of the lead screw then, in a predetermined direction is effective to drive the carriage along the lead screw by virtue of the threaded engagement between the slide and the screw.

Mechanism including an operating rod is provided for placing the slide and thus the cars into engagement with the lead screw. Frequently however, the lead screw, during the course of its rotation and while engaged with the slide, may of its own accord, drive the slide out of threaded engagement without any manipulation of the operating rod.

Accordingly, it is a particular object of the present the lead screw and the slide in the engaged position until disengaged by manipulation of the operating rod.

It is a further object of this invention to provide a means for positively locking or latching the carriage into engagement with the lead screw.

Other objects and features of the present invention will become more apparent when considered in conjunction with the appending drawings wherein,

Fig. 1 is a transverse sectional view of a sequential controller similar to the controller disclosed in said patent and showing to advantage the controller housing, the back panel, the lead screw, the carriage including its slide and the latch mechanism. Note that the slide and thus the carriage are shown in the engaged or driving position with respect to the lead screw;

Fig. 2 is a sectional view of Fig. 1 as viewed in the plane of line 22;

Fig. 3 is also a sectional view of Fig. 1 as viewed in the plane of the line 3-3; and

Fig. 4 is a view of a portion of Fig. 1 showing the slide and the lead screw in the disengaged position.

As is apparent in Figs. 1 and 2, a linearly arranged sequential controller with which the present invention may be associated may be arranged as shown and described in said Puerner et al. patent and may comprise a housing A having a back wall B molded of a suitable insulating material such as Bakelite. Mounted in the housing A and arranged to move in a linear path within the housing is a U-shapcd bracket or carriage C. The carriage pivotly supports a contact block D which in turn supports a plurality of spring biased trolleys or wipers E. The trolleys E are constantly maintained in sliding electrical contact with a corresponding number of linearly arranged bus bars F. The back wall B is formed, as by molding, with a plurality of linearly arranged cams or contoured strips G. The cams G may be engaged and traversed in linear fashion by a corresponding number of followers H formed integral with at least one contact of a plurality of pairs of spring contacts J. Thus, it is apparent that current is provided to each pair of contacts J from the bus bars F through the trolleys E while the contacts are actuated to accomplish a switching action by the cooperation between the contoured cams G and the corresponding followers H as the followers traverse the able motor.

The carriage C has side walls C and C and a bottom wall C The bottom wall C is attached to a carriage plate C by means of a plurality of screws C The studs of the screws C are disposed within longitudinal slots A and A provided in the housing A. The aforesaid construction permits longitudinal movement of the carriage C within the housing A. A bracket 10 is fixedly secured to the interior of the U-shaped bracket C by means of lugs 10a on said bracket and slots in the side and bottom walls of said carriage. The carriage C is adapted to be moved linearly with respectto the housing A and its back wall B by means of a worm or lead screw 18 which is engaged by a latch member or slide 11 slidably mounted on the bracket 10. The bracket 10 is formed with a slot 10b and the slide 11 is formed with a slot 11b to permit the lead screw 18 to pass through the carriage C. The slide has cars 16 and 17 which are adapted to engage grooves in the worm 18 so that the worm as it is rotated by a synchronous electric motor, such as disclosed in the Puerner et al. patent, moves the carriage longitudinally with respect to the housing A and its back wall B. Thelatch member 11 has slots 13 and 7 13a therein and the bracket 10 has lugs 12 and 12a thereon whereby the latch member 11 is slidably secured to the bracket member 10. The latch member 11 has a struck out car 22 thereon and the side wall C of the carriage C has an ear 23 thereon, and a tension spring 21 is attached between the ears 22 and 23 so that the latch member 11 is urged toward the side wall C of the carriage as seen in Fig. 1. It is to be noted that the pin 12 and the slot 13 provide a stop for the latch member when it is urged toward the side wall C of the carriage C and the side wall C acts as a stop for the latch member 11 when it is moved upwardly as seen in Fig. 1.

Means are provided for moving the latch member 11 to engage and disengage the control block D from the back wall B and the ears 16 and 17 from the lead screw 18. This means comprises a plunger or operating rod 14 secured to said carriage and associated with means on said latch member for moving the ears 16 and 17 out of engagement with the lead screw 18. The plunger or operating rod 14, as seen in Fig. 2, extends through an opening 14a in the carriage plate 0,, and through an opening 14b in the bottom wall C of the U-shaped carriage C. The plunger 14 has a plurality of fingers 24a, 24b and 240. The finger 24a is adapted to engage a cam surface 24d on a cam bar 24s when the plunger is moved to the left as seen in Fig. 2 to move the cam bar 24a away from the contact block D to disengage said cam block from the back wall B of the housing A. The finger 24b extends through an opening 24 in the stationary bracket member 10 and is adapted to engage the contact block D when the plunger or operating rod 14 is moved to the right as seen in Fig. 2. The finger 240 is ofiset with respect to the main body portion of the plunger or operating rod and has a cam surface 24g thereon which cam surface is adapted to engage a pin 19 suitably secured to the latch member 11. The offset finger 24c passes through an opening 24h in the stationary bracket member 10. The pin 19 has a shaft 19a and a rivet head 29 and the pin fixedly secures a thin metal plate 28 and another metal plate 26 to the latch member 11. The plate member 26 has an outwardly extending lug 27 formed integrally therewith and said lug has an ear 27a depending therefrom. The thin plate 28 has extending therefrom a strip 23a which is C-shaped in order to clear the sides of the latch member 11 and the strip extends for the length of the depending ear 27a of the plate 26. Since the strip 28a is made of thin metal, it is capable of being flexed to the right as seen in Figs. 1 and 2 and is capable of returning to its position shown in Fig. 2 after having been flexed outwardly. When the carriage C is in its engaged position as seen in Fig. 1, the strip 28a is disposed between the ear 27a and the finger 24c and occupies most of the space between these two elements. The finger 24c cannot move laterally and when the member 11 for any reason tends to move upwardly as seen in Fig. 1, the depending ear 27a, which is fixedly secured to the member 11, is stopped by means of the strip 28a and the finger 24c.

Thus it can be seen that if during the rotation of the lead screw 18 while the slide 11 is engaged therewith, there is a tendency for the ears 16 and 17 to work their way out of engagement with the screw, the strip 28a by virtue of its cooperation with the finger 24c and the ear 27a of the plate 26 acts to hold the slide 11 and thus the ears 16 and 17 in place.

At times, when the operating rod 14 is depressed (pushed inwardly to the position shown in Fig. 1.) permitting the slide 11 to approach the position shown in Fig. 1, the ears 16 and 17 do not immediately engage a groove in the threaded lead screw 18. The lugs hang-up momentarily upon the surface defininglthe outside diameter of the lead screw 18 and thereafter find their way into threaded engagement.

During this interval when the ears 16 and 17' are not" in-actual threaded engagement but in contact with the outside diameter of the screw, and while the operating rod is depressed, it is apparent that interference occurs between the right end of the finger 24c and the strip 28a (Fig. 1). The end of the finger will abut the underside of the strip 28a. Since the strip is resilient, it is merely pushed outwardly by the end of the finger 24c. As soon as the ears 16 and 17 engage a groove in the lead screw, the slide is moved downwardly by the spring 21 and the strip 28a slides off the end of the finger 24c and snaps inwardly between the finger and the ear 27a of the plate 26 thus locking the slide in threaded engagement with the lead screw.

It is to be noted that a particular feature of the present invention resides in the fact that it is no longer necessary to fashion the ears 16 and '17 so that they complement and threadedly engage the lead screw 18 precisely. The elimination of this requirement obviously lends itself to a considerable saving of time and money when one recogni'zes that controllers embracing the present invention are produced on a mass production basis.

Stated otherwise, in utilizing the lock or latching device of the present invention, it is no longer necessary for the ears 16 and 17 to be precisely aligned with the lead of the thread formed on the screw 18. In fact, if, during the course of the rotation of the screw 18 with the lugs in the engaged position, there is friction or slight interference between the side walls of the groove with which the lugs are engaged and the sides of the lugs, there is absolutely no danger that the slide will be driven out of engagement (thus disengaging the carriage and disabling the controller), because the slide 11 is locked in place by the action of the strip 28a. Withdrawal of the ,operating rod, of course, moves the finger 240 to the left as seen in Fig. 1 and into a position wherein the strip 28a may move upwardly. At the same time, the cam surface 24g engages the pin 19 of the slide '11 and moves the slide upwardly and out of engagement with the lead screw 18.

It is anticipated that various arrangements and representations of the present invention may be undertaken Without departing from the spirit and scope of the appended claims.

We claim:

1. In a sequential controller for a laundry machine of the type wherein a contact carriage is adapted to be placed into threaded engagement with a linearly arranged lead screw: means including an operating rod and a slide mounted in the carriage for effecting said threaded engagement, said rod being movable 'to an operated position wherein the slide and the screw are engaged, spring means for urging said slide into engagement with said screw means for rotating the lead screw whereby the carriage is encouraged to move along the longitudinal axis of the screw, and lock means formed integral with the slide and cooperating with the operating rod when the rod is in the operated position for locking the slide with the lead screw.

2. In a mechanism wherein a carriage is moved in a linear direction by meansof a rotated screw, means for coupling, said carriage to said screw for a driving engagement therewith, said coupling means comprising a rod movably mounted on said carriage and having one portion thereof defining a cam surface, a cam pin adapted to be engaged by said cam surface, a slide, said cam pin being connected to said slide, means for supporting saidv slide on said carriage, said slide being movable laterally thereon and having a pair of ears situated on opposite sides of a longitudinal transverse opening therein so as to be engageable with the teeth of said screw, biasing means adapted to urge said slide into its screw engaging position, the lateral displacement of said slide from said screw being caused by movementof said rod which moves said cam pin and said slide in a lateral direction thereby placing said ears into and out of engagement'with' said screw, means for positively locking said slide into engagement with said screw, said means comprising a member fixedly secured to said slide and engaging a por tion of said rod when said rod is in its slide engaging position to prevent said slide from moving transversely and out of engagement with said worm.

3. In a mechanism wherein a carriage is moved in a linear direction by means of a rotated screw, means for coupling said carriage to said screw for a driving engagement therewith, said coupling means comprising a rod movably mounted on said carriage and having one portion thereof defining a cam surface, a cam pin adaptedto be engaged by said cam surface, a slide, said cam pin being connected to said slide, means for supporting said slide on said carriage, said slide being movable laterally thereon and having a pair of ears situated on opposite sides of a longitudinal transverse opening therein so as to be engageable with the teeth of said screw, biasing means adapted to urge said slide into its screw engaging position, the lateral displacement of said slide from said screw being caused by said rod which moves said cam pin and said slide in a lateral direction thereby placing said ears into and out of engagement with said screw, an opening in said carriage, said one end of said rod being adapted to pass through said opening when said rod is moved to a position whereby said cam surface moves said cam pin and consequently said slide to a screw engaging position, a stop element fixedly secured to said slide and spaced laterally from said opening, a resilient element fixedly secured to said slide and having one surface thereof disposed over said opening when said rod is in its screw disengaging position and another surface being disposed adjacent said stop element, said resilient element being adapted to rest in the space between said stop element and said one end of said rod when said slide is in its screw engaging position to prevent transverse movement of said slide, said resilient element permitting said one end of said rod to pass through said opening in the event said slide does not move to its screw engaging position when said rod is moved, due to said ears engaging the top of the teeth of said screw.

References Cited in the file of this patent UNITED STATES PATENTS 826,835 Crump July 24, 1906 1,721,227 Manley July 16, 1929 2,641,661 Puerner June 9, 1953 2,716,352 Wilson Aug. 30, 1955 

